The dynamic interfacial phenomena during high-temperature reaction between an Fe-Al alloy droplet and a CaO-SiO2-Al2O3 slag were analyzed by evaluating the thermocapillary, solutocapillary, and electrocapillary effects. The magnitudes of these effects were determined using the local equilibrium model and utilizing kinetic data to determine local composition, temperature, and electrical potential. The electrocapillary effect was found to be dominant. It contributed approximately 85 pet of the maximum interfacial depression while the solutocapillarity contributed 15 pet. The thermocapillary effect was found to be negligible. In this work, the local gradient of interfacial tension along the interface due to the solutocapillary effect was estimated, i.e., Δγm-s = 274 to 440 mN/m over a 1- to 2-μm distance.